I applied online, and one of the best parts was how quick they were to respond after every step. After each part of the interview process, I got emailed with the next step within a day.
The first step was a phone screen.
After that was a "tech challenge" which was different than most companies I applied to. I met one of their engineers in a Google Hangout, she gave me a written list of 3 questions/problems and gave me 45 minutes to work on them, after which she came back and we discussed my answers.
The questions were very relevant to what I would be doing at the position and included having me retrieve certain information from their API using their documentation, and how I would reply to potential support inquiries.
After that, I was invited to an all-day on-site interview at their NYC office. The email invitation included a detailed schedule of who I would be meeting and what they would be interviewing me on.
During the on-site, I had 5 interviews altogether, as well as lunch with the whole NY based team.
The interviews included two technical interviews, one interview about my background, one interview with the Developer Support team which focused mostly on support scenarios, and a meeting with the founder/CTO where we spoke about the company.